(1) Field of the Invention
This invention relates to a method for producing aromatic hydrocarbons by introducing alkyl groups into alkyl or alkylene side chains of substituted aromatic hydrocarbons. More particularly, the invention relates to a novel method for alkylating side chains of substituted aromatic hydrocarbons with ethylene and/or propylene in the presence of metallic sodium catalyst.
(2) Description of the Prior Art
As the methods for producing new aromatic compounds by alkylating side chains of aromatic compounds with alkali metal catalysts, there are disclosed several examples of reactions in Herman Pines, "Base Catalyzed Reactions of Hydrocarbons and Related Compounds", Academic Press, New York.
Furthermore, there are prior art disclosures on the alkylation reaction of side chains using alkali metal catalysts: British Pat. No. 857,894 in which alkali metals and iron compounds are used; J. Amer. Chem. Soc., 82, 4912 (1960) and J. Org. Chem., 22, 48 (1957) in which polycyclic aromatic compounds are used as promoters; and British Pat. No. 1,269,280 in which alkali metals carried on potassium compounds are used.
When the above carrier-supported catalysts are used for chemical reaction, it is necessary to put catalysts on carriers beforehand.
In the field to deal with metallic sodium, the danger of metallic sodium is well known. From this fact, it is not too much to say that to accomplish the method of handling the metallic sodium safely is inevitable for carrying out the reaction using the metallic sodium in the chemical industry in which large quantities of inflammable substances are employed. From the viewpoint of the possible industrial practice to put the dangerous metallic sodium on fine carrier particles, it is necessary to pay close attention to the handling of metallic sodium as well as to several apparatus in order to avoid the inflammation when not only a trace quantity of water but also a very small quantity of oxygen exist.
That is, all of the above processes to put the metallic sodium on carriers, are done without the presence of any solvent, the so-called dry process. The dry process, however, involves the danger of spontaneous combustion of metallic sodium. Meanwhile, a method to use liquid ammonia as a solvent has been proposed, however, it also involves much difficulty in the pretreatment and the handling of liquid ammonia.